1. Field of the Invention
The invention relates to the design of integrated circuits, more particularly to a method for fabricating a customer-configured integrated circuit, and to a customer-configured integrated circuit for exclusive use by a customer.
2. Description of the Related Art
It is not unusual for integrated circuit vendors and manufacturers to provide the same functional type of integrated circuit to competing customers. In order to guard against piracy among competing customers, integrated circuit vendors and manufacturers need to develop customer-configured integrated circuits. In this way, customers can use the customer-configured integrated circuits that function in the same manner but have different configurations in the development of their own application systems. Therefore, unscrupulous customers can be prevented from copying the designs of others, and from producing and selling copied designs that use the customer-configured integrated circuits.
Conventionally, there are three methods available for programming an integrated circuit. First, a hard-wired programming scheme, such as a fixed functional setting in the functional design stage, is available to specify a particular function or configuration. However, this scheme suffers from lack of flexibility, and integrated circuit vendors and manufacturers incur a tremendous increase in production management costs because different mask layers are required, and because different raw products are produced when fabricating different customer-configured integrated circuits. Second, a software programming scheme is available in which a system driving software can change the programming of the integrated circuit anytime during the operation of the application system. While this scheme offers flexibility, it cannot provide sole protection and proprietary use for integrated circuits of the same functional type. Third, a non-volatile programming scheme is available in which a non-volatile memory, such as a flash memory, is programmed by the user. Information in the non-volatile memory does not get lost when the application system is turned on or off. Since the configuration of the integrated circuits shipped to all customers is fixed, sole-protection or proprietary use is weak because the programmed information can be easily stolen.
Customers need customer-configured integrated circuits for exclusive use so as to protect themselves from piracy. On the other hand, integrated circuit vendors and manufacturers require a simple production process to supply different customer-configured integrated circuits of the same functional type to different customers so as to incur little overhead. As such, the conventional integrated circuit programming schemes are inadequate for both the customers and the integrated circuit vendors or manufacturers.